Laying Forming Process Of GF/HDPE Pyramidal Lattice Structures

As a new type of structure,the composite lattice structure has the advantages of high specific rigidity and high specific strength.It has a large internal porosity and interconnects with each other.It can embed small components and reduce weight.Therefore,it is widely used in many fields such as aerospace,construction facilities,automobile transportation,and sports facilities.This paper proposes the in-situ layered consolidation molding process of thermoplastic composite materials to prepare the intermediate core of the pyramid al lattice structure,designs and builds thermoplastic composite material laying platform,and carry out the influencing law of the parameters of the laying process on composite laminates.Based on the self-designed pyramidal lattice structure,the pyramidal lattice structure was prepared by using the laying platform,and its mechanical performance test,theoretical prediction formula derivation and failure mode analysis were performed.The main work includes the following aspects:Firstly,this article summarizes the current research status of the fabrication process of composite lattice structures,introduces the development process and basic principles of fiber placement technology and in-situ consolidation technology,and clarifies the research content and significance of this topic.Secondly,the in-situ layered consolidation molding process of thermoplastic composite materials using a combination of fiber placement technology and in-situ consolidation technology is studied.The functional requirements and basic composition of the thermoplastic composite material placement experimental platform are analyzed and summarized,and detailed analysis and design of each component module is completed,and builds a thermoplastic composite material laying platform that meets the design requirements.Next,taking composite laminates as an object,combining single-factor experiments and three-factor four-level orthogonal experiments,the short-beam method of interlaminar shear strength test method and micro-morphological observation were used to investigate the influence of laying parameters on the process parameters.The results show that: The interlaminar shear strength of the part rises first and then decreases with the increase of the forming pressure,and then rises and then decreases with the increase of the heating temperature,and continues to decrease with the increase of the laying speed.The optimal combination of process parameters in the experimental range is: heating temperature of 430?,forming pressure of 0.2MPa,and laying speed of 60mm/min.The primary and secondary order of the influence of the process parameters on the experimental indicators is: the impact of the laying speed is the largest,the pressure is the second,and the heating temperature is the smallest.Finally,the core of the pyramidal lattice structure is prepared by using the thermoplastic composite material laying platform,and the panel and the core are bonded and formed using cementation technology to obtain a sample of the pyramidal lattice structure.The standard manufacturing process is summarized,and the strength theory prediction formula of the sandwich structure is flattened,the compression performance of the pyramidal lattice structure is tested,the compression strength of specimens with different core relative densities is obtained.It is known that the greater the relative density of the core under the same configuration,the better the compression performance.Finally,by observing the failure phenomenon of the test piece,the failure modes of compression load of pyramid al lattice structure with different core relative density are summarized.